If you like us, please share us on social media or tell your professor. Consider building or adopting a Wikitext for your course like Prof. Dianne Bennett from Sacramento City College demonstrates in this video.

ChemWiki: The Dynamic Chemistry Hypertext > Under Construction > Demonstrations > Additional Demos > Chemiluminescence-- Singlet Oxygen

Chemiluminescence-- Singlet Oxygen

Chemical Concepts Demonstrated



  • A: Cl2 Cylinder
  • B and C: Gas washing bottles
  • E: 30% H2O2 and 6M NaOH
  • F: 6M NaOH

Open the main valve on the Cl2 cylinder. 


A red glow will be observed.

Explanation (including important chemical equations)

The red glow is caused by the formation and decay of singlet O2.

Cl2 + H2O2 --(OH-)--> O2 + 2 HCl (the oxygen formed here is singlet oxygen)

Singlet oxygen is an excited form of oxygen.  Oxygen normally has two unpaired electrons in its outermost orbital.  Upon receiving this exitation, the two electrons occupy a single molecular orbital. Two singlet oxygens go to the ground state by a two molecule, one photon transition.  This is actually a form of radioactive decay, and it causes the red glow.

2 O2(1Dg) -> 2 O2(3Sg) + hv (630 nm)



You must to post a comment.
Last modified
10:28, 2 Oct 2013



(not set)
(not set)
(not set)






This material is based upon work supported by the National Science Foundation under Grant Numbers 1246120, 1525057, and 1413739.

Creative Commons License Unless otherwise noted, content in the UC Davis ChemWiki is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. Permissions beyond the scope of this license may be available at copyright@ucdavis.edu. Questions and concerns can be directed toward Prof. Delmar Larsen (dlarsen@ucdavis.edu), Founder and Director. Terms of Use